Fluid-pressure jack



/ Aug. 4, 1925. 1,548,559

R. W. SIMPSON FLUID PRESSURE JACK Filed MELIGh 1S, 1925 2 Sheets-Sheet l lllllll.

WITNESSES INVENTOR v W Hobart. W SLJTL/OSOIL- ATTORNEYS Aug. 4, 1925. 7 1,548,559

R. W. SIMPSON FLUID PRESSURE JACK File Marsh 13, 25

lfi PRESSURE INVENTOR 78oberl' I V. 5L77L U60TL ATTORNEYS Patented Aug. 4, 1925.

UNITED STATES PATEN oFFi-ea.

7 ROBERT WILLIAM SIMiSON, OF MEMPHIS, TENNESSEE, ASSIG-NOR, 1'0 MECHANICAL DEVICES COMPANY, OF MEMPHIS, TENNESSEE.

FLUID-PRESSURE .1" ACK.

Application filed March 13, 1925. Serial Ito-15,223.

a multiple stage, fluid-pressure machine for 15 the purpose of lifting objects, the lifting capacity being'determined by the weight and character of the object, which consideration in turn will determine the size of the machine.

Another object of the invention is to provide a jack wherein the pressure of the actuating fluid is exerted upon both ends of a movable plunger simultaneously;

Other objects and advantages, appear in the following specification, reference being had to the accompanying drawings, in 'which v Figure 1 is a side elevation of the improved jack, illustrating the use of a table therewith for the purpose of lifting such objects as automobiles.

Figure 2 is a central vertical section of the jack, the plunger being in the retracted position.

the plunger is in the fully extended position.

Figure 41 is a cross section on the l1ne el'4 of Figure 2.

Figure 5 is a cross section on the line 5-5 of Figure 2.

Reference has been made to the invention as an expansible-fluid machine. It is intended to operate the machine by means of a fluid etc. In view of this-circumstance the maohifie might well be termed a pressure-fluid jac In carrying out the invention provision is made of a cylinder 1 which is composed of upper and lowersections 2 and 3. The confronting eiids of the sections have flanges 4 and 5 which are secured by bolts; 6 or the jacks and it consists of the constructions, I

Figure 3 is a detail sectional view in which under pressureas for example, oil, air, water,

fectly rigid, and in fact the larger sizes of the jack will be imbedded in the earth approximately u Figures 1 an 2. In the smaller sizes of the jack the cylinder 1 will constitute the stationary member.

.The hub 7 contains a packing 8 which is compressed by a gland 9 upon the applica tion of pressure by nuts 10 on a plurality of studs 11 stationarily mounted in the hub. The packing prevents the leakage of fluid under pressure past the plunger 12. The plunger is movable, and constitutes the element by which the lifting is done.

Internal enlargements 13 and 14. in the upper section 2 of the cylinder 1 have a stabilizing function in respect to the movable plunger 12. The plunger is tubular, being composed of a length of suitable pipe.

' Both ends are threaded. The upper end car:

ries a head 15 to which the table 16 (Fig. 1) may be suitably applied, the lower end car rying a cap 17. Both the head and cap provide closures for the ends of the tubular plunger. The ca 17 has a loose fit in the lower section 3 of the cylinder and serves as a guide, supplementing the stabilizing funcmentione-d.

A suitable cap 18 closes the lower end of the section 8. A. nut 19 in the axial center of the cap 18 provides the anchor for the stationary tubular'piston rod 20. The upper end of the rod carries a stationary piston 21 which fits the interior of the tubular plunger 12 and in reference to which the plunger is movable.

The hub 7 and its associated parts; and the piston 21 are stationary elements between which the plunger 12 is slidable.

A plurality of vents 22 in the stationary piston rod immediately below the piston 21 prpvide for the relief to atmosphere of air oiother' substances that might be entrapped in the air space betweenthe piston rod and tubular plunger. Such release would occur upon the upward movement of the cap 17 with the plunger. The hollow 'pistonrod is open to the pit 23 at the'bottom, and in to the hub 7 as shown inv 'tions of the enlargements 13 and 14 already tains oil upon which pressure is im osed by compressed air in a tank 26". The ischarge of compressed air is controlled by a threeway valve 26".. The respective pipes dlf charge the fluid so that upward ressure 1s exerted against the cap 17 an these parts constituting the first and second sta e lifts.

he supply pipes 24 and 25 join a common pipe 27 with which other pipes 28 and 29 have connection. The first pipe leads from the small end of a differential valve casing 30 and has a globe valve 31, the'second pipe leading from the reservo1r and having a globe'valve 32. The valvecasmg 30 also has a pipe connection 33 with the reservoir, whic valve 34. v

A pipe 35- rovides communication between an annu ar groove 36 in the enlargement 14 and enlarged end of the valve casin 30. The enlargement 14 carries a sultab e packing 37- immediately below the groove 36. pipe connection 38 which furnishes communication with one side to the space beneath the cap 17. A packing and gland 39 m ake a tight oint where the connection 38 passes through the cap 17. A packing and gland 40 similarly provide atight joint where the stationary piston rod 20 passes through.

Situated in the valve casing 30 is a differential piston 41, in other words a piston by virtueof'the communication of the pipe consisting of parts of different diameters.

The piston is normally retracted as in Figure 2, but when the tubular plunger 12 rises to the height in Figure 3, fluid pressure from the first stage lift enters the groove 36 connection 38, imposing a superior pressure upon the piston 41 so that it moves to the right andv shuts off thesuplply of fluid to the common pipe 27. The va ve 32 (Fig. 2) is normally 0 osed. The operation is readily understood. The jackis supposed to normally assume the retracted position in'Figures 1 and 2. The head 15 of the movable tubular plunger 12 may be suitablyf'equipped to lift any kind of object. It is not necessarily confined to act as a mount for a table 16 as in Figure 1,

but may be uipped for other lifting purposes. All 3? the valves 31-, 32 and 34 are now closed. The three-way air valve-26 is open.

Upon desiring to extend the plunger 12 the operator opens the valves 31 and head 15,

\ are held-inany extended position connection carries a globe he plunger 12 has a suitablenuance new enters the common pipe 27 whence it is distributed to both pipes 25 and 24. These pipes discharge the pressure fluid in the space beneath the cap 17 and head 15 where it exerts a simultaneous lifting force upon both ends of thevplun er 12. The cap 18 and piston 21 are per ectly rigid andstationary, and provide the abutments against which the pressure fluid acts. The respec tive faces beneath the cap 17 and head 15 are regarded as first and second lifting sta es. It is to be noted that each stage has its '1n-' dividual supply of pressure fluid.

As the plunger 12 rises in respect to the stationary cylinder 1 and stationary piston rod 20 the air, oil or the like, that may be pelled at the vents 22 to the interiorof the rod 20 whence it passes to the pit 23 which is regarded as the equivalent to atmosphere. The movable plunger 12 and head 15 closing the valves 31 and 34. .1 Should it be desired to lower these parts the valve '32 is opened and three-way valve 26" is turned to permit the return, of fluid from the first and second stages to the reservoir 26, and the escape of residual air from tank .26 to atmosphere.

Provision is made against the event of merely the operator failing to close either? valve 31 or 34, or both, in o der to sto the extension of the plunge 12. Sue failure would result in the cap 17 ultimately striking the internal enlargement 14 and caus-' ing serious damage to the jack. As soon a the side opening of the pipe connection 38 registers with the annular groove 36, pressure from the first st e moves the valve piston 41 over to the rig t (Fi 3), automatically closing the pipe 28 and s utting off the flow of'pressure fluid to the ipes 24 and 25.

The value of theinternal enlargements 13 and 14 and of'the guide cap 17 is readily seen. These parts hold the movable plunger perfectly stationary when fully extended,

and prevent any .unsteadiness when sub jected to side ressuresv The cylinder 1 1s shown imbed ed up to the hub 7, but it is to be understood that the differential valve casing 30, the various pipe connections thereof and the reservoir 26 are not intended to be imbedded. These parts will be situated on the surface where access may be had thereto.

Whilethe construction and arrangement of the improved jack is that of a generally preferred form, obviously modifications and changes may be made without departing from the spirit of the invention or the scope of the claims.

I claim Y 1. A jack comprising a stationary cylinder, a plston in annular spaced relationship, I

a plunger which is ,SliditblB in the space between the cylinder and piston, and means for stationarily mounting the piston within the cylinder and supplying fluid under pressure for the operation of the plunger.

2. A jack comprising a stationary cylinder, a piston in annular spaced relationship to the cylinder, a tubular plunger slidable in the space between the cylinder and piston, a,t-ubular piston rod having vents adjacent to the piston, means incorporated in the cylinder in which said rod is anchored, thereby holding the piston stationary, a cap on the lower end of the plunger, a head on the upper end of the plunger, and a pressure fluid supply pipe assing axially through the piston rod and supplying a space between the piston and head thereby to extend the between the hea and piston passing through the vents and out by way of the tubular piston rod and a space around the supply 1 e. P A jack comprising a stationary cylinder having a cap at one end, a piston in annular spaced relationship to the cylinder, a tubular, plunger slidable in the space hetweenthe cylinder and piston, a head closing one end of said plunger and opposing one side of the piston, a cap closing the other end of the plunger and opposing the other side of the piston,-a tubular piston rod stationarily supporting the piston within the cylinder and having vents adjacent to the 7 piston, means carried by the cylinder in which the piston rod is anchored and through which it has communication with the exterior of the cylinder, and a source of pressure fluid supply including pipes to discharge fluid simultaneously into the cylinder between the cylinder-andv plunger caps and into the plunger between the piston and plunger head, the latter supply pipe passing freely through the stationary piston rod in spaced relationship thereto and being secured to the piston and leaving a passage through which air may escape from the vents upon the advance of the plunger cap toward the piston.

4:. A jack comprising a. cylinder, a movable plunger having a cap which fits in the cylinder, an annular groove on the interior of the cylinder facing the plunger, a source of pressure fluid including a pipe discharging into the cylinder beneath said cap, a pipe connection providing communication from the side of the plunger above the cap lunger, the air entrapped to the space between the cap, and means including a pipe for conducting the fluid from said groove when said plunger raises sufliciently in the cylinder to bring the side of said connection in registration with the groove thereby providing a pressure release.

5. A jack comprising a cylinder, a movable plunger having a cap which fits in the cylinder, an annular groove on the interior of the cylinder facing the plunger, a source of pressure fluid including a pipe discharging into the cylinder beneath said cap, a pipe connection providing communication from the side of the plunger above the cap tothe space between the cap, and means including a. pipe for conducting the fluid from said groove when said plunger raises sufliciently in the cylinder to bring the side of said connection in registration with the groove thereby providing a pressure release, and a differential valve operated by the fluid thus released to automatically shut ofl the supply of fluid. to the cylinder.

6. A jack comprising a pair of tubular sections one of the sections having an internal enlargement at one end and at the opposite end having a corresponding internal enlargement and a hood, means including flanges and bolts by which the dissimilar sections are secured together to constitute a cylinder, a tubular plunger movable in the cylinder in contact with said enlargements, a packing gland associated with the hub to provide a joint aroundthe movable plunger, a cap closing the lower end of the plunger being sufliciently large to engage the interior of one of the sections for guidance, a head closing the upper and closed end of the plunger, a piston situated inside of the plunger, a tubular piston rod by which the piston is carried, means included in the cap at the lower end of the last section having means in which the tubular rod is anchored and through which communication to the atmosphere may be had, vents in said tubular rod providing said communication from the interior of the plunger, and means to supply fluid under pressure for the operation of the. plunger, said means including a pipe entering the cylinder cap for the discharge of fluid beneath the plunger and a pipe extending axially of the tubular rod and discharging above the piston so that fluidexerts pressure on the head at the upper. end of the plunger. 4

/ ROBERT WILLIAM SIMPSON. 

